Drop Guillotine, et al.

A series of chokes came to mind when I was reading the thread about head control off the sprawl. I enjoy using the harness (under and overhook, clasp hands, chest on their back) from the sprawl. And I just so happen to have a scan of a Grappling Mag page that explains the drop guillotine from here:

I don't know why he's hooking the arm with his foot. I would just throw both legs over the back. You can also jump into it instead of stepping into it, but it takes better agility.

What makes this choke so gnarly is that its power comes from you straightening your leg against the back of your head. It has a high neck crank potential too.

I just so happened to catch some shots of a purple belt going for this on a brown belt.

If you're doing gi, you can collar choke this way by grabbing the opposite collars with four fingers inside (so your palms are down) and jumping up to put the legs over from there. This is shown in Green Whale Production's Global Jiu-Jitsu DVD (a seminar with 6 BJJ black belts showing techniques).

If you want to get fancy (and I know you do), you keep feed your own gi skirt through and use it to do this choke.

I was taught a variation where the right arm was deeper towards the neck and you overhand grip your own wrist. we would then circle counter-clockwise and place the knee in back of the opponent's (rt)elbow to block him from pulling his arm free while we threw the right leg over the head and then rolled back while simultaneously throwing the left leg over their back (or for larger opponents) right leg to keep them from rolling out while tightening the choke.
the choke was finalized by twisting the shoulders away from the opponent and/or pulling one's own arm (as if it were a rope)

Baret Yoshida does several drop guillotines in his new book/DVD, since he favors the front headlock. One setup I found interesting was how he would go for an arm-inside guillotine, but as he was pulling guard, they would roll to their back to escape. As they did this, he would sit out and try to finish the guillotine with them on their back circling towards their head (like a cattle catch). But if they escaped this by turning to their knees again, he'd step over their head as they came up and go to the drop guillotine.

There are also simpler combos, like going for a drop guillotine and switching to an arm-inside guillotine when they pull their head out from under the leg.

I learned this choke from John "The Rev" Jensen, who got it from Tyrone Glover. In the California Pro-Ams from a few years back, Tyrone Glover chokes Andy Wang unconscious with this choke really fast. The hard part seems to be getting the good cross-face first. After that the rest seems pretty easy.